1986 K10 4 speed to 5 speed
 

Hi,

Picked up a ‘86 K10 (really more of a mut but you get the point) with a LS swap and a SM465/NP208. The front and rear are standard 1/2 ton with 3.08’s.

Looking to do some upgrades and would like to understand my options. The truck is my local grocery getter and runs on limited fire roads, basically a “NH Mall crawler”

To start the upgrades I’d like to toss a 5-speed in there with the right t-case and front/rear diff/gear.

Would like to know what my tranny/t-case/diff options are.

I have read if I want to go with a late model 5-speed I need to run a ford front end as the diff is on the opposite side versus the early stuff. Not opposed to that but I think the ford front ends are hard to come by

I don’t mind Swapping the ring/pinion but I haven’t done the research to understand if I can stuff a 3.73 in the carrier.

I also really can’t remember how good the early 5-speeds/t-cases are? I know I drove an assload of them but my memory is relative to the time!

Any help appreciated, I’m sure all this info is here but my search’s haven’t had great returns. Will take any links to info as well, thanks!

Also it runs on 33’s, not planning to change that.

Re: 1986 K10 4 speed to 5 speed
 

If you have a 12 bolt rear ,it would have a series 3 carrier..will work up to 3.73s
But you most likely have a 10b rear which will work with 3.73s also
No need for a Ford axle.. you can use a chevy nv4500 and pass drop transfer case..
It will bolt to the LS, if you can scrounge up the factory parts..
I never could find enough OEM parts to do it.
That leaves the option of using advanced adapters..its pricey
Another option,also pricey, is the new tr4050 and pass drop transfer case...
its made to replace nv4500 which hasnt been made in yrs,and is getting harder to find

Re: 1986 K10 4 speed to 5 speed
 

If your truck came from the factory with the 465, Use an early NV4500, your t case, and the original clutch master, and adapt the line to the early 4500 slave.
You will hear all sorts of mis information about the front shaft hitting the slave cylinder, but I ran an early NV4500 in my stock height truck for almost 15 years without a single issue. I did the conversion in the late 90s and when I sold the truck in 13-14 it was still going strong

Re: 1986 K10 4 speed to 5 speed
 

Well now we are getting into the mut part of the truck… it’s an 89 1 ton cab with an ‘86 frame.

The 465 came with the ‘89 cab, it was a 1 ton dump. Not sure where the 208 came from.

Thanks for this info, I’ll search up more info on the tranny/tcase info provided and see what I get.

Also the truck has a 3” lift.

Re: 1986 K10 4 speed to 5 speed
 

This is the truck, I should also mention I mostly build 2WD so my 4WD knowledge needs work.

Re: 1986 K10 4 speed to 5 speed
 

Not bad...not bad...
Just be aware if you follow thru with all this parts swapping, its gonna get expensive..
Been there-done that...

Re: 1986 K10 4 speed to 5 speed
 

Sounds like the 465 is the later (about 1980-newer) style, so should be a 32 spline output shaft (compared to the earlier 465 which had a 10 spline output) I only know the NP208 to have either a 27 spline (350t/700r4) input or 32 spline 400t/manual trans)

The later 85 up trans crossmember will work with the nv4500/208

Its a pretty straight forward swap. Heck I did it in the 90s (pre internet days) so you shouldn’t have a problem.

Re: 1986 K10 4 speed to 5 speed
 

Oh I’m well aware, been at this long enough to recognize the pattern. It’s all good so far, I’m just starting with my research and plan.

Re: 1986 K10 4 speed to 5 speed
 

The nv4500 will be the easiest swap. If you get a 92-95 nv4500 with the 5.125" input bearing retainer, it can be used with your existing bellhousing and clutch assembly. You will need to drill and tap the transmission face for a different bolt pattern, and those bolts will need to be installed inside the bell instead of from the rear.

The 96-07 nv4500 used a 5.6" input bearing retainer, so it won't fit the sm465 bell at all. Use the correct nv4500 bell with the internal slave cylinder on these, or buy an aftermarket bell from Advance Adapters.

The nv4500 will be the same exact length as your current sm465, so the crossmember and driveshafts won't change at all. Also, your existing np208 will bolt right up to a nv4500 with no modifications at all.

The only other two five-speeds that are of any account for full-size pickups, are the zf5(used in Fords) and the tr4050.

The tr4050 has something funky going on with the t-case flange or spline count. I'm pretty sure there are RH-drop t-cases that will fit it, but do your research on that. I 'think' that an early-90's dodge t-case will bolt up, and will be RH-drop. The tr4050 is basically an updated nv4500. The basic layout is the same, but with a much-improved fifth gear retention system.

The zf5 is a well-regarded transmission, but you will need an adapter plate to connect it to a GM engine. I found an adapter plate online with a quick search, but it costs $650. You'll also likely need an adapter plate to connect it to a RH-drop t-case as well. This transmission will be too expensive after all those adaptations to be worth messing with.

Re: 1986 K10 4 speed to 5 speed
 

Great info, like the idea of using my 465 bell/208 and have 0 prob tapping the tranny!